Thursday, January 17, 2013

U-blox PCI-5S - a cheap GPS module for your projects

[Update] I have found the timepulse output!

The U-blox PCI-5S is the cheapest GPS module on eBay right now (although you have to buy an additional antenna).
At first glance it seems useless for microcontroller projects because it's a mini PCIe card, but as it turns out it has an easily accessible UART port that can be connected to a microcontroller.

Here's the pinout:

The USB device is a standard CDC ACM serial port.

RX/TX pins are a second (independent of USB) UART port running at 9600bps by default.

You can use u-center to modify the module's configuration, for example set the update frequency to 4Hz.

PCI-E and Mini PCI-E edge connectors have both USB and PCI-E data on them. Looking at the pins used on the edge connector, I believe this card only uses the USB data. The other pins aren't used. I don't know how well links work here, I'll try anyway:http://pinoutsguide.com/Slots/mini_pcie_pinout.shtml

I just looked at the U-Blox site. Because the card available on eBay was made by/for Toshiba, there's no direct documentation for it on the U-Blox site, but the ones on eBay might be based on the now-discontinued 5S U-Blox GPS module. Here's a link to a page titled, "Previous generation GPS receiver modules." It's essentially a table comparing various no-longer-produced modules and their features. The feature I'm looking for is either a 1 (or 4) pulse-per-second (PPS) signal and/or the precision-timing feature--either or both of which can be used to make hyper-accurate GPS-discipined oscillators. It's not clear to me that the cheapies on eBay can do that. Does anyone have any knowledge of these devices who can comment?

It seems that this module does support a timepulse signal - it can be configured through u-center.Maybe the output is one of the other test points, I didn't find anything when I tested them, but the manual says the signal is only present when there is a reliable fix, I will try that again and report back.

There is a high probability that it's possible, the u-blox product catalog shows a half size version of this card.But the PCB has more than 2 layers, so it's a mystery how the traces are routed in that area.

Lots of people bought this card after HaD published my tip, maybe someone is brave enough to try it. :)

What would be interesting is whether this module supports the output of 'Raw' data output, which would allow more accurate (off board) position computation - L1 GPS can get down to around 1cm accuracy on a good day!

hello nice finding :) when i first saw the post on HDA i searched ebay and i bought one ~2 months later it arrived but i have some questions (cause i don't wan't to kill it :P)

1. are the inputs 5V tolerant or only 3.3v ? 2. does it require an external antenna ? 3. the pictures show two test points for usb connection but i guess i have to provide 3.3v to power the device ?

anyway thanks again for sharing

someone said they couldn't find any listing on ebay i bought my from here http://www.ebay.com/itm/250866889973?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 - the shipping (at least for my country) is more that the actual module but is still cheaper than other gps modules

You mean the update frequency?You need to install u-center software.From there select the "configuration view" and there you will have lots of configuration options, "RATE" is the option for changing update frequency.

I got mine in the post recently, and got it working. One thing that stumped me for ages was receiving a lot of "txbuf alloc" errors. I've fixed it now - it happens when the baud rate is too low for all the information to be sent. Setting the baud rate to 38400 instead of 9600 fixed it for me.

I've just order it on ebay. But i'm not sure for the antenna.Maybe, the GPS internal antenna for the ipad 3 or ipad mini will be ok. It's very inexpensive on ebay:Like this one (1.39$)http://www.ebay.com/itm/New-GPS-Antenna-Signal-Flex-Cable-Repair-Fix-Replacement-Parts-For-iPad-3-3Gen-/280919335233?pt=Other_Tablet_eReader_Accessories&hash=item416818e141

Or this one: (2.89$)http://www.ebay.com/itm/New-Replacement-GPS-Antenna-Signal-Flex-Ribbon-Cable-Fit-For-Ipad-mini-/140899956140?pt=Other_Tablet_eReader_Accessories&hash=item20ce4ab5ac

But i'm not completly sure that the connector is a UFL (but it looks like on the pics)

Thanks Emeryth, I found a default setting thing and it worked with that, but I'll keep your file. I think I got carried away clinking stuff.... clicked cold start and wasn't patient enough for it to find sat's.

I should have payed more attention :) if anyone wants to configure this device to output only GGA and RMC data this are the steps to follow (using the u-center tool):1. go to view-> configure view2. select MSG(Message) 3. from the dropdown box select which strings you don't want to output and deselect on which interface you don't want to output and remember to hit send after every change

It's strange because in the ublox center show me the satellites conected and state of the signal. When disconnect the antenna can't see the satellites like should be.when i go see the data send on a console don't show any satellites connected.

I am seeing the same thing with a module that I purchased. Using the u-center program and Emeryth's configuration file, I am currently "Tracking" 8 SVs but none of them are 'Used" and I am not showing any Lat/Lon information and the SkyView window shows up blank.

Did any of you manage to solve this problem? My module finds all the satellites in a second, but then fails to get a fix, even when left for hours. Looking in the u-center monitor section, it seems it also doesn't get the ephemeris data from the satellites. The signal strength for most of the satellites varies by ~10dB+ from sample to sample.

1. USB-Supply:surely i have to reduce the supply voltage from 5v to 3v3, i do that with a low-voltage-drop regulator (MCP1700-3302E) its designed for 250mA. is that enought? how much does that board draw (with/without active antenna)?

2. USB-D+/D-:i'm not soo sure about the usb data lines. what is better to use, inline resistors (with which value? 72R / 68R / 33R? i've seen severel configs) or z-diodes to GND? and do i even need them?

I just want to confirm that you can cut the PCB!! If you remove the sticker on the top, there is a Ublox logo, I cut along that logo with my dremel and it still works fine without that inch of un-used PCB!

this is what i was looking for. I've ordered one already :) btw, I've fount this thingy on ebay: http://www.ebay.com/itm/1pc-Import-GPS-Module-SIRF3-TTL-RS232-/281190259803 and I'm wondering if it could work with an atmega... sry for bad english :)

I'm really stuck. I am unable to get a lat/long from the unit. I pickup sat's but they only appear in the sat signal monitor as blue bars and not green bars as expected. If I take the unit outside I was tracking 13 'blue' sats but apparently they don't provide position info? Tried just about everything in the config file.

Since most modules are really old, the almanac and ephemeris data might be outdated. They will get updated when receiving data from the satellites. This takes at least 12.5 minutes. You can get a faster time to fix if you download current data from the web and send it to the module. Use u-center > Tools > AssistNow Offline, select "14 Days AlmanacPlus" and "Flash update". After clicking "OK" you should get a position fix in short time.

After Emeryth published the pinout, I also started to experiment with this board. I found out that you can update the firmware using the LEA-5 firmware version 6.02 from the u-blox web site. The module also works very well with the patched firmware version EXT_G50_602_LEA-5H.bdbfccefb9dbd8395dec7adece53c1f9.bin. This version enables the output of raw data for use with rtklib for real-time kinematic and precision positioning. I am currently using the module with a Mini-PCIe-to-USB adapter for 3G WWAN cards like this one:http://www.ebay.com/itm/MINI-PCI-E-TO-USB-PCI-E-TO-SIM-3G-TEST-CARD-WWAN-TEST-CARD-upgrade-veersion-/251378335831?pt=LH_DefaultDomain_0&hash=item3a87510057You can then use the standard drivers from the u-blox web site for Windows. They provide a virtual COM port. Please note that updating the firmware just worked using the physical serial port of the Mini-PCIe card, it did not work using the USB adapter.

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Hi, I have an idea and would need your help to let me know what exactly i need to purchase to get this working:

- gps unit that will be placed outdoors in/on a small plastic construction. it can be either outside on the construction or inside, but the construction will be outdoors, so it will be there when it rains/snows.- on the construction there will be a solar panel to power the gps- the gps needs to send its location 24/7 so that a person coming with a mobile phone will be able to receive its signal and find it

thats all. can you please let me know:- does the gps have to be outside on the construction in order to send signal or can it "see" through the construction so it can be inside (so it wont have to be waterproof)?- how can i supply power from the solar panel to the gps?- what product (gps+antenna+..?) do i need to purchase for this to work?- + some mobile app to interpret the data..?